WEDNESDAY, June 23 (HealthDay News) -- Advanced lung cancer is notoriously hard to treat, but a team of Japanese scientists reports that a cancer drug known as Iressa was significantly more effective than standard chemotherapy for patients with a certain genetic profile.

These patients have an advanced form of the most common type of lung cancer -- non-small cell lung cancer -- and a mutation of a protein found on the surface of certain cells that causes them to divide. This protein -- known as epidermal growth factor receptor (EGFR) -- is found in unusually high numbers on the surface of some cancer cells.

The researchers focused on gefitinib (Iressa), which stops the protein receptor from sending a message to the cancer cells to divide and grow. In their study, reported in the June 24 issue of the New England Journal of Medicine, the drug had a better safety profile and improved survival time with no cancer progression in a significantly higher percentage of patients than did standard chemotherapy.

Researchers from the respiratory medicine department at the Tohoku University Hospital in Sendai, Japan chose to investigate gefitinib in part because standard cancer treatments --including surgery, radiation and chemotherapy -- fail to cure most cases of non-small cell lung cancer.

From clinical trials, the researchers also knew that non-small cell lung cancers in people with a sensitive EGFR mutation were very responsive to gefitinib, but little was known about the medication's safety profile or effectiveness compared with standard chemotherapy.

For this reason, Dr. Akira Inoue and his colleagues focused on 230 patients with the EGFR mutation and metastatic non-small-cell lung cancer; the patients were treated in 43 different medical facilities between 2006 and 2009 throughout Japan. In a randomized case-control study, half were given gefitinib, while the others received standard chemotherapy.

After an average follow-up of about 17 months, the research team found that while 73.7% of the gefitinib patients responded positively to their treatment, only 30.7% of the chemotherapy patients did so.

The mean survival time with no cancer progression was significantly higher among the gefitinib group -- 10.8 months, compared to 5.4 months among the chemotherapy group. In addition, one and two-year survival rates were, respectively, 42.1% and 8.4% among those in the gefitinib group, compared to 3.2 and zero among those in the chemotherapy group.

There was not a significant difference in the overall two-year survival time -- 30.5 months for the gefitinib group compared with 23.6 months in the chemotherapy group. However, the progression-free survival time and safety profile were significantly better in the gefitinib group, researchers found.

Chemotherapy patients were also significantly more likely to suffer severe toxic effects, including anemia and nerve damage, from their treatment than were those taking gefitinib (71.7% vs. 41.2%).

The most common side effects for the gefitinib group were elevated aminotransferase enzyme levels and rash, but six patients (5.3%) developed the serious condition interstitial lung disease, and one woman died of it. Noting that the disease was associated with gefitinib treatment, researchers stressed that "every patient treated with [this type of drug] should be monitored for this toxic effect."

Overall, the authors concluded, gefitinib was a safer and much more effective way to tackle this type of lung cancer in patients with the EGFR mutation, and that this treatment should be considered the first-line treatment for such patients.

"This is a beginning of the ideal individualized treatment for metastatic non-small-cell lung cancer," said Inoue. "Patients treated with gefitinib would live much longer, with better quality of life, than those treated with cytotoxic chemotherapy."

Dr. Norman H. Edelman, chief medical officer for the American Lung Association, described the Japanese effort as "an important finding that could change the practice of treating lung cancer."

Edelman noted that for non-small-cell lung cancer -- that is, most lung cancers -- that has mutations in the gene,"[the researchers] think this should be the front-line therapy. And that is a very important conclusion that could change medical practice, because up until recently cancer therapy was just taking a elephant gun and just hoping you kill just the cancer and not the elephant. This is different. This is honing in on a specific receptor."

"The effect here is more dramatic than we usually see in cancer chemotherapy studies," Edelman added. "[The researchers] significantly delayed the onset of new disease, they significantly increased disease free-progression, and they clearly show that this new medication was more effective than the controlled medication."

"And what's good about this is that it was a real-life study," he said. "They didn't compare the medication to placebo. They compared it to standard chemotherapy, which is a much more rigorous test of its usefulness and its efficacy."